Divers began probing Grandaddy Lake Thursday morning in search of the body of a 20-year-old man believed to have drowned Wednesday.

The Duchesne County Sheriff's office is withholding the identity of the man, pending notification of the next of kin. He is reportedly from the Wasatch Front area.The man was fishing with a 25-year-old friend at the lake in the High Uintas Wilderness Area, about 12 miles north of Hanna. Sheriff Clair Poulson said the man apparently decided to swim to an island in the lake but got into trouble about 150 yards out from shore.

The friend went to his aid but was forced to turn back when he began suffering cramps. Poulson said the victim got to within 50 yards of the shore when he disappeared.

A search and rescue group spent the night at the lake and began efforts to locate the body early Thursday.